About RAID

RAID, an acronym for Redundant Array of Independent Disks, is a technology that provides increased storage functions and reliability through redundancy. This is achieved by combining multiple hard disk drives into a logical unit, where data is distributed across the drives in one of several ways called RAID levels.

When a group of independent physical hard disk drives are set up to use RAID technology, they are in a RAID array. This array distributes data across multiple hard disk drives, but the array appears to the host server as one single storage unit. Creating and using RAID arrays provides high performance, such as the expedited I/O performance, because several drives can be accessed simultaneously.

RAID drive groups also improve data storage reliability and fault tolerance compared to single-drive storage systems. Data loss resulting from a drive failure can be prevented by reconstructing missing data from the remaining drives.

The following list describes some of the most commonly used RAID levels:

•RAID 0: block-level striping without parity or mirroring

Simple stripe sets are normally referred to as RAID 0. RAID 0 uses striping to provide high data throughput, especially for large files in an environment that does not require fault tolerance. RAID 0 has no redundancy and it provides improved performance and additional storage without fault tolerance. Any drive failure destroys the array and the likelihood of failure increases with more drives in the array. RAID 0 does not implement error checking, so any error is uncorrectable. More drives in the array means higher bandwidth, but greater risk of data loss.

RAID 0 requires a minimum number of two hard disk drives.

•RAID 1: mirroring without parity or striping

RAID 1 uses mirroring so that data written to one drive is simultaneously written to another drive. This is good for small databases or other applications that require small capacity but complete data redundancy. RAID 1 provides fault tolerance from disk errors or failures and continues to operate as long as at least one drive in the mirrored set is functioning. With appropriate operating system support, there can be increased read performance and only a minimal write performance reduction.

RAID 1 requires a minimum number of two hard disk drives.

•RAID 5: block-level striping with distributed parity

RAID 5 uses disk striping and parity data across all drives (distributed parity) to provide high data throughput, especially for small random access. RAID 5 distributes parity along with the data and requires all drives but one to be present to operate; drive failure requires replacement, but the array is not destroyed by a single drive failure. Upon drive failure, any subsequent read operations can be calculated from the distributed parity so that the drive failure is masked from the end user. The array will have data loss in the event of a second drive failure and is vulnerable until the data that was on the failing drive is rebuilt onto a replacement drive. A single drive failure in the set will result in reduced performance of the entire set until the failing drive has been replaced and rebuilt.

RAID 5 requires a minimum number of three hard disk drives.

•RAID 10: a combination of RAID 0 and RAID 1

RAID 10 consists of striped data across mirrored spans. A RAID 10 drive group is a spanned drive group that creates a striped set from a series of mirrored drives. RAID 10 allows a maximum of eight spans. You must use an even number of drives in each RAID virtual drive in the span. The RAID 1 virtual drives must have the same stripe size. RAID 10 provides high data throughput and complete data redundancy but uses a larger number of spans.

RAID 10 requires a minimum number of four hard disk drives and also requires an even number of drives, for example, six hard disk drives or eight hard disk drives.

72ThinkServer Hardware Maintenance Manual

Page 83 Page 85
Page 84
Image 84
Lenovo 388, 441, 393, 392, 391, 389, 387, 390 manual About RAID
Page 83 Page 85

389, 441, 388, 392, 391 specifications

Lenovo has established itself as a leader in the tech industry, particularly in the realm of laptops and PCs. Among its impressive lineup, the Lenovo series 387, 390, 393, 391, and 392 stands out for their innovative features, robust performance, and user-centric designs. These models cater to a range of users, from casual users to professionals who require high performance and reliability.

The Lenovo 387 is designed with versatility in mind. It comes equipped with an Intel Core processor that delivers snappy performance suitable for everyday tasks and even some heavy lifting with multimedia applications. The display features vibrant colors, making it perfect for streaming media or working on graphic design. Additionally, the 387 incorporates Lenovo’s advanced thermal management technology that ensures efficient cooling, preventing the device from overheating during intensive tasks.

Moving on to the Lenovo 390, this model emphasizes portability without compromising power. Weighing significantly less than its counterparts, the 390 is ideal for users who are always on the go. Its long-lasting battery life means users can stay productive throughout the day without searching for a power outlet. The 390 also features a high-resolution touchscreen, enhancing user interaction and providing a modern computing experience.

The Lenovo 393 further amplifies productivity features with its emphasis on connectivity. It comes with multiple USB ports, an HDMI output, and cutting-edge Wi-Fi technology for seamless networking. This model also boasts Lenovo's proprietary software, which simplifies file sharing and enhances collaboration, making it a strong choice for team-oriented projects.

For users interested in superior graphics and gaming performance, the Lenovo 391 is equipped with a dedicated GPU. This feature allows it to handle the latest games and graphic-intensive applications seamlessly. With an expansive display and high refresh rate, users can enjoy an immersive visual experience. Moreover, its customizable RGB backlit keyboard adds a touch of personalization.

Finally, the Lenovo 392 represents the pinnacle of balance between high-end features and affordability. It integrates smart AI capabilities that optimize device performance based on user habits, ensuring that it runs at optimal capacity. The 392 also prioritizes security with biometric login options and integrated privacy features, making it a trustworthy choice for sensitive tasks.

In summary, Lenovo's 387, 390, 393, 391, and 392 models showcase the brand's commitment to innovation, performance, and user satisfaction. Each model targets specific needs, ensuring that there is a suitable option for every type of user, from students to professionals and gamers. With advanced technologies and thoughtful designs, Lenovo continues to set the standard in the competitive laptop market.
Top Page Image Contents